In an ultrasound apparatus, therapeutic ultrasounds are emitted via a diagnostic probe kept in contact with the body surface of a subject, and ultrasound images (e.g. tomograms and M-mode images) are reconstructed on the basis of reflected echo signals generated from the subject. Also, a target region is uninvasively treated by emitting therapeutic ultrasounds onto the subject via a therapeutic probe.
In performing an ultrasound therapy, a diagnostic probe and a therapeutic probe are usually arranged alongside each other on the body surface of the subject in order to emit therapeutic ultrasounds while checking the target region by its ultrasound images (see, e.g., Japanese Patent Application Laid-Open No. 5-220152).
However, arranging a diagnostic probe and a therapeutic probe alongside each other on the body surface as in the conventional practice results in a difference in scanning coordinates between the diagnostic ultrasounds and the therapeutic ultrasounds according to the difference between the contact positions of the two probes. Moreover, since the contact positions of the two probes are determined by the operator as desired, the difference in scanning coordinates is not constant. Therefore, while finding out the difference in scanning coordinates between the two probes on every occasion of therapeutic action, the coordinate position of the target region is determined on the basis of ultrasound images acquired with the diagnostic probe, the coordinate position is converted into the coordinate system of the therapeutic probe, and therapeutic ultrasounds are emitted onto the target region accordingly. As a result, particular care should be taken in manipulating the therapeutic probe and the diagnostic probe, inviting inconvenience in the use of probes.